The present invention relates to a new and improved method of making a mold and more specifically to a method in which a section of ceramic mold material is separated from another section of ceramic mold material.
During the making of a mold it may be necessary to separate one section of a layer of ceramic mold material from another section of the layer of ceramic mold material. For example, when a pour cup is made, a generally conical pattern is covered with a layer of ceramic mold material. It is necessary to separate the portion of the layer of ceramic mold material overlying the circular base of the conical pattern from the remainder of the layer of ceramic mold material in order to open the pour cup. This has previously been done by a time consuming abrading or cutting operation.
A mold assembly having a plurality of separate sections is disclosed in U.S. Pat. No. 4,066,116. In forming the various sections of the mold assembly, a wax pattern is repetitively dipped in a slurry of ceramic mold material. The resulting wet layer of ceramic mold material is separated into sections by wiping away a portion of the layer of ceramic mold material. After the ceramic mold material has dried, the mold sections can be separated at the location where a discontinuity was formed during the step of wiping away the wet ceramic mold material.
Another mold having a plurality of sections is described in International Patent Application Serial No. PCT/US86/00166 entitled "Method and Apparatus for Casting Articles" filed Jan. 28, 1986 for Lawrence Graham, Richard Skelley, Daniel Fetsko, and Ronald Ardo. The mold disclosed in this application includes separable upper and lower sections. The mold may be formed by repetitively dipping a wax pattern in a slurry of ceramic mold material. After the ceramic mold material on the pattern has dried, the ceramic mold material is cut to separate the upper and lower sections of the mold.